An estimated 80,000,000 American adults (one in three) have one or more types of cardiovascular disease (CVD); 7,900,000 have a history of myocardial infarction (American Heart Association). Stem cell therapy is a promising approach for myocardial infarction repair, and the use of stem cells to repair a damaged heart is now mainstream in current cardiac research. Unfortunately, thus far direct injection of stem cells into the fibrotic area of infarcted hearts has met with limited success, probably due to the low retention and survival of stem cells in the necrotic areas, together with the limited cardiogenic differentiation and functional integration of delivered cells within the host heart tissue. To solve these problems, a tissue engineered scaffolding method has recently been proposed, involving the use of synthetic tissue scaffoldings with stem cells seeded and subsequently embedded within the bioengineered graft framework. However, limited success has been achieved due to inadequate experience in combining synthetic scaffolds with stem cells and limited knowledge of how to improve the geometry and composition of scaffolding to favor revascularization and improve the graft microenvironment for enhanced viability, growth, and differentiation of stem cells. Our proposal addresses these limitations with a new strategy that combines use of biodegradable elastomeric and oxygen-releasing scaffoldings for mesenchymal stem cell therapy. To this aim, we will use our hybrid bio-printing technology of polymer electrospinning and microjet cell printing to fabricate a durable stem cell based multilayered 3-D cardiac patch. In this bioengineered construct, the scaffold serves as an efficient stem cell carrier and 3-D elastomeric physical structure for myocyte growth and electro-mechanical coupling. The inclusion of calcium peroxide oxygen-releasing nanoparticles in our scaffoldings improves the microenvironment for enhanced survival of stem cells and their integration with the injured cardiac tissue. Therefore, we propose 4 Specific Aims: 1. Prepare and characterize scaffold materials for a cardiac patch. 2. Optimize incorporation of oxygen releasing particles into scaffolds for maximum oxygen delivery and minimal toxicity. 3. Fabricate a composite cardiac patch by using the hybrid fabrication biotechnology. 4. Conduct in vitro evaluation of the bio- engineered cardiac patch. Taken together, the proposed project will improve current stem cell therapy for myocardial infarct by providing cells with a stable delivery vehicle and an amenable local environment that enhances and regulates their proliferation and differentiation for cell-based tissue regeneration and repair. In addition, this effort promises future methodological improvements by bio-printing critical signaling peptides and other molecules for use in scaffolds designed to repair soft tissue injuries. PUBLIC HEALTH RELEVANCE: An estimated 80,000,000 American adults (one in three) have one or more types of cardiovascular disease (CVD); 7,900,000 have a history of myocardial infarction (American Heart Association). Stem cell therapy is a promising approach for myocardial infarction repair, and the use of stem cells to repair a damaged heart is now mainstream in current cardiac research. The proposed project will improve current stem cell therapy for myocardial infarct by providing cells with a stable delivery vehicle and an amenable local environment that enhances and regulates their proliferation and differentiation for cell-based tissue regeneration and repair.